Flexible self-expandable stent using shape memory alloy and method and apparatus for fabricating the same

• US 20020147489A1
• Filed: 03/18/2002
• Published: 10/10/2002
• Est. Priority Date: 04/04/2001
• Status: Active Grant

• Current Assignee: Taewoong Medical Company Limited (Olympus Corporation)
• Original Assignee: Taewoong Medical Company Limited (Olympus Corporation)
• Inventors: Hong, Soon-Hyung, Jung, Jin-Wook, Park, Jae-Hyung, Shin, Kyoung-Min, Lee, Jong-Taek, Son, Woong-Hee
• Granted Patent: US 6,974,472 B2
• Time in Patent Office: Days
• US Class Current: 623/1.2
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

Disclosed herein is a flexible self-expandable stent using shape memory alloy for expanding stenosal portions and method and apparatus for fabricating the same. The self-expandable stent using shape memory allow, comprises a first cylindrical stent member comprised of a first wire formed of super elastic shape memory alloy, the first wire being bent a large number of times while being extended upwardly and downwardly a large number of times, so the first wire forms a plurality of variable rhombic spaces by forming a plurality of intersections for causing the first wire to be intersected with itself to resist longitudinal constriction of the first cylindrical stent member and a plurality of interlocked points for causing the first wire to be interlocked with itself at spaced positions to allow longitudinal constriction of the first cylindrical stent member; and a second cylindrical stent member comprised of a second wire formed of super elastic shape memory alloy, the second wire being diagonally extended in parallel with the previously positioned first wire and passed alternately under and over the first wire so as to divide each of a plurality of rhombic spaces formed in the first cylindrical stent member into four equal parts, thereby preventing the first and second cylindrical stent members from being separated from each other.

Claims

1. A method for a flexible self-expandable stent using shape memory alloy, comprising the steps of:

detachably attaching a plurality of projected pins at all intersections of a jig cylinder between circumference dividing lines and length dividing lines at their one-side ends, said circumference dividing lines and said length dividing lines being set by regularly dividing a circumference and a length of said jig cylinder, and selecting a projected pin situated at the uppermost position of said cylinder as a start point;

fabricating a first cylindrical stent member comprised of a first wire formed of super-elastic shape memory alloy so that said first wire is intersected and interlocked with itself at spaced positions to form a plurality of variable rhombic spaces, said step of fabricating said first cylindrical stent member comprising,

the first process of passing said first wire through said start point, bending said first wire by extending said first wire by a diagonal length of and passing said first wire by a first projected pin, bending said first wire by diagonally downwardly extending said first wire by a diagonal length of and passing said first wire under a second projected pin, bending said first wire by diagonally upwardly extending said first wire by a diagonal length of and passing said first wire over a third projected pin, and bending said first wire by diagonally downwardly extending said first wire by a diagonal length of 2 and passing said first wire under a fourth projected pin,

the second process of bending said first wire by diagonally upwardly extending said first wire by a diagonal length of and passing said first wire over a fifth projected pin, bending said first wire by diagonally downwardly extending said first wire by a diagonal length of and passing said first wire under a sixth projected pin, bending said first wire by diagonally upwardly extending said first wire by a diagonal length of and passing said first wire over a second projected pin, bending said first wire by diagonally downwardly extending said first wire by a diagonal length of 2 and passing said first wire under a seventh projected pin, and bending said first wire by diagonally upwardly extending said first wire by a diagonal length of and passing said first wire over an eighth projected pin,

the third process of extending said first wire downwardly and upwardly six times each by a diagonal length of ,

the reversed process of said first process,

the reversed process of said second process,

the fourth process of extending said first wire downwardly and upwardly four times each by a diagonal length of , and

the process of connecting both ends of said first wire to each other;

fabricating a second cylindrical stent body, in which a second wire is diagonally extended in parallel with said previously positioned first wire and passed alternately under and over said first wire so as to divide each of a plurality of rhombic spaces formed by said first cylindrical stent member into four equal parts, and said second wire is connected at its both ends; and

fabricating a hollow cylindrical body by joining said first cylindrical stent member with said second cylindrical stent member so that said first wire and said second wire pass under and over each other while being separated from each other so as to be bendable but longitudinally constrictable, and heat-treating said hollow cylindrical body to memorize its original shape.

2. The method according to claim 1, wherein said first and second wires are each connected at both ends to each other by inserting said ends into a sleeve and pressing them.

3. A self-expandable stent using shape memory alloy, comprising:

a first cylindrical stent member comprised of a first wire formed of super elastic shape memory alloy, said first wire being bent a large number of times while being extended upwardly and downwardly a large number of times, so said first wire forms a plurality of variable rhombic spaces by forming a plurality of intersections for causing said first wire to be intersected with itself to resist longitudinal constriction of said first cylindrical stent member and a plurality of interlocked points for causing said first wire to be interlocked with itself at spaced positions to allow longitudinal constriction of said first cylindrical stent member; and

a second cylindrical stent member comprised of a second wire formed of super elastic shape memory alloy, said second wire being diagonally extended in parallel with the previously positioned first wire and passed alternately under and over the first wire so as to divide each of a plurality of rhombic spaces formed in the first cylindrical stent member into four equal parts, thereby preventing said first and second cylindrical stent members from being separated from each other.

4. An apparatus for fabricating self-expandable stent using shape memory alloy, comprising:

a cylinder having the same diameter and length as those of a self-expandable stent to be fabricated;

a plurality of assembly grooves formed along circumference dividing lines and a length of said cylinder, said circumference dividing lines being set by regularly dividing a circumference of said cylinder;

a plurality of projected pins detachably implanted at all the intersections between said circumference dividing lines and length dividing lines at their one-side ends, said length dividing lines being set by regularly dividing a length of said cylinder; and

a fixing projected pin implanted on an uppermost portion of said cylinder.

5. The apparatus according to claim 4, further comprising a plurality of assembly auxiliary grooves, said assembly auxiliary grooves being each formed between two neighboring assembly grooves.